1. Technical Field
The present invention relates to a liquid jet head for discharging liquid from nozzle holes to record an image or text on a recording medium, and a liquid jet apparatus including the liquid jet head.
2. Background Art
Presently, as a liquid jet apparatus, there is provided an inkjet recording apparatus (for example, printer or facsimile machine) which discharges ink (liquid) toward a recording medium such as recording paper that is transferred in a predetermined direction to record an image or text. The recording apparatus performs recording by supplying ink from an ink tank via an ink supply tube to an ink jet head (liquid jet head) and discharging ink from nozzle holes of a head chip included in the ink jet head toward a recording medium.
In the above-mentioned head chip, a plurality of channels into which ink is filled are formed in parallel lines at intervals, and the nozzle holes which communicate with the channels are formed. Side walls of the above-mentioned channels are formed of a piezoelectric material, and have drive electrodes formed thereon.
The ink jet head including the head chip structured as described above further includes control means for controlling drive of the above-mentioned head chip. The control means includes a drive circuit board including a drive circuit formed thereon for driving the head chip and a flexible printed board including signal lines formed thereon for connecting the drive circuit and the drive electrodes. In the ink jet head including such control means, by applying drive voltage from the drive circuit via the signal lines to the drive electrodes, the side walls are deformed to increase the pressure in the channels, thereby causing ink in the channels to be discharged from the nozzle holes.
In the foregoing operation of the ink jet head, because viscosity of the above-mentioned ink varies depending on the temperature, an amount of ink discharged from the nozzle holes varies depending on the temperature of the ink. Therefore, conventionally, an inkjet head includes a temperature sensor which is attached to a head chip, for detecting the temperature of ink in the head chip. In an inkjet head including such a temperature sensor, the temperature sensor detects the temperature of ink, the detected value is sent to the drive circuit, the drive circuit determines the magnitude of the drive voltage based on the detected value, and the drive voltage is applied to the drive electrodes. This may keep the amount of discharged ink constant (see, for example, the below-mentioned Patent Document 1).
Patent Document 1: JP 2003-182056 A
However, in the conventional technology described above, because the temperature sensor and the drive circuit are connected via a lead wire, when the ink jet head is manufactured, the temperature sensor with the lead wire, which is packaged on the drive circuit board, is manually routed to the head chip to be fixed using an adhesive or the like, which reduces the production efficiency and is a cause of an increase in cost.
Further, because the lead wire is routed and the temperature sensor is fixed to the head chip as described above, it is necessary to, for example, dispose a damper member or the like in order not to obstruct the work, which restricts the structure of the ink jet head.
Further, when volatilized ink adheres to the lead wire, there is a possibility that the lead wire is corroded. In this case, there is a possibility that the temperature detection becomes incorrect.
A liquid jet head and a liquid jet apparatus according to the present invention have been made in view of the above-mentioned conventional problems, and objects of the present invention are to be able to reduce costs by improving the production efficiency, to be able to reduce restrictions on the structure of the liquid jet head, and to cause incorrect temperature detection to be less liable to occur.